Ian Turnbull Ker (30 August 1942 – 5 November 2022)[2][3] was an English Catholic priest, a former Anglican and a scholar and author.

[4] He was generally regarded as the world's authority on John Henry Newman, on whom he published more than 20 books.

Ker was regarded as the leading authority on Saint John Henry Newman, on whom he published the universally acknowledged definitive biography.

He was the author of The Catholic Revival in English Literature 1845-1961, Mere Catholicism, and G.K. Chesterton: A Biography.

On this last book, the late Christopher Hitchens reviewed that "Professor Ker's spirited and double-barreled attempt at a rehabilitation" of Chesterton "is enjoyable in its own right.